Process for cracking hydrocarbon oil



Patented July 27, 1,926.

UNITED STATES PATENT OFFICE.

CARBON P. DUBBS, OF l'WIIILMETTE, ILLINOIS, ASSIGNO'R T0 THE UNIVERSAL OIL PROD- UCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA..

'l PROCESS FOR CRACKING IIYDROCARBON OIL.

Application mea octobr 21, 1922. serial No. 595,947.

This invention relates to improvements in a process for cracking hydrocarbon oils and refers more particularly to a process in which relatively high boiling point oils are converted into oils of lower boiling point,

such as gasoline and the like.

Among the salient objects of thel invention are:

To provide a process in which the oil is primarily raised to a cracking temperature in the heating zone and is then 'passed to a vaporizing chamber, from which the vapors evolved are passed throughdephlegmating and condensing stages,

To provide a process in which the oil vaporized under'pressure is passed through v a dephlegmating stage and thence through stages of reduced pressure whereby subseuent to the first pressure' dephlegmation t e oil is subjected to fractionation in suc-A cessive stages ,under reduced pressure and the lighter products of the oil removed therefrom,

To provide a process whereby a high grade gasoline-like distillate may be obtained due to the subsequent fractionation under reduced or atmospheric pressure,

To' provide a process ,in which these lighter products may be drawnl olf and'collected l0 or returned and re-cycled either through thev heating stage or through dephlegmating stages.

The single gure is a diagrammaticside elevational view of the apparatus.

Referring" to the drawings, the oil to be y treated is introduced through the line 1, controlled by a valve 2, andis sprayed into the dephlegmator 3 at about midway of its height. This reduces the possibilityof any 0 of the lighter fractions contained in the raw oil from .being carried the preceding nace is ofthe side-tired type, having a com- .a fr action ating column over with the heatedvapors which are rising through the de which it is drawn off,A

in the tank so, from bustionchamber 12 in which the heat is generated. The combustion gases pass through the duct 13 and circulate downwardly over the heating tubes and out through a flue not shown. The oil after being raised to a cracking temperature in the heating zone is passed to an expansion or vaporizing chamber line 15. This transfer line has interposed therein a valve 16 for control of the liquid and pressure conditions if desired.

The vaporizing chamber consists of an ,enlarged tank which is equipped with trycocks 17 anda residuum controlled by a valve 19. The vapors evolved in the chamber 14 rise through the vapor line 20'in which is interposed the valve 21 and are introduced to the bottom of the dephlegmator 3 through which they rise and are subjected to the reiluxing action of the incoming raw oil and returned distillate as will hereinafter be explained.

From the vapors is separated condensate which ilows back with the raw oilfor retreatment in the heating tubes. The uncon-l densed portion of the vapors passes off through the line 22 controlled by the valve 23 and is introduced to the lower portion of 24. This fractionating column is similar in construction to the dephlegmator 3. The upward travel of thel vapors is obstructed by perforatedvpans or trays as shown at 25. Enclosing the fractionating column is 'a casing or shell 26 which is equipped with adjustable shutters 27 by means of which the temperature .of the air surrounding the v phlegmatmg or turned distillate formed by subsequant dephlegmation of thevapors. The li uid tion separated from the vapors i t is actionating column is drawnj 0E t line 28 controlled by valve29 and is collected which it may be withdrawn through a. va,1ve` 3l-and passed te hrough the.

14 ythrough the transfer draw-off line 18 refluxing action of -a rel storage or returned through the line 32, 48, pump-34 and line 35` to the line 8 communicating with the heating tubes.

An alternatev method of handling this condensate is to close the valve 36 and with-l draw the liquid through the line 37 and charge it through the pump 38`and line 39 to the top of the dephlegmating column 3. This condensate is charged to the dephlegmator near its top as it contains relatively refractory liquid and is not egsily carried over in a vapor state by the reux vapors passing -oli" from" the top of the dephlegmator. v

In a similar manner. the vapors uncondensed in the fractionatin column 24 pass off through the line 40 inw ich is interposed a valve 41 and are introduced to the bottom of -a second fractionating column 43, which is similar in design to the fractionating eolumn 24. It. is also surroundedby a shell or housing which has adjustable shut-ters for controlling thehtemperature of the column. In a like manner, the liquid material separated out in this column is drawn off through a line 44 controlled by a valve 45 and is collected inea tank 46, from which-it may be similarly Handled as the condensate separated out in the column 24; that-is, it may be drawn oi thbugh a line 47 to storage, returned to the heating coils through a line 48.con'trolledby 'a valve49 o r recharged into the Itop ofthe fractionating trol valve 52.

column 24 by means turn line 51.

of the pump 50 and rein which,y is interposed a con- From the .second stage of fractionation the l .vapors pass olf through a line 53 to a final condensate stage, which consists' of a condenser coil 54 housed. ina water condenser box 55.' The liquid products from this final condensing action pass l'down through the pipe'56 to the receiver 57. vValves 58 and 59 are interposed in the pipes 53 and 56 ,respectively. The receiver is equipped with .a pressure reliefvalve'GO, pressure gauge 61,

liquid level gauge 62 and a. draw-0E valve 63. A second draw-ot line 64 furnishes a means for re-cycling the distillate collected in .the receiver by means ofa ,pumpl 65 back to the fractionating column 43 through a pipe 66. Liquid ,level gauges 67 are positioned on the sides of the tanks 30 and 46 ,-for ascertaining the tanks and pressure gauges 68, 69 and 70 are level of the oil in the tapped into Vthe top of the dephlegmator 3 and ractionating columns 24 and 43 respectvely.- A y In operating the process as explained, the oil, which may be of any character, whiclr be eectively and commercially cracked ma .bylieat and pressure,is charged into thede- P.

I leglnating stage and after' serving as. a reiiuxmg medium, together with what-'redux condensate. .itcmay celled tberaln'g' pag.599

to the heating stage where it is raised to a conversion temperature ranging from 500 F. to 900 F., according to the character'of the oii' and the pressures imposed. The oil is then conducted 'to the va-porizing chamber where it is permitted lto collect into asubstantial body, the vapors rising through the ,Vapor line to the dephlegmating stage while theliquid level in the chamber may be controlled by the residuum draw-off Valve 19. The vapors, after being subjected to dephelegmation under' pressure. substantially the same as that maintained in the heating stage or at a differential pressure, if desired,

somewhat lower than' that in the heating or' vaporizing stages, are passed over through the line 22 in whichis interposedthe reduction valve 23. Here the pressure onl the vapors is reduced and they are directed ,through the successive ystages of fraction'- ation which takes place in the columns 24.

ltake place at` atmospheric pressure. The

conditions of operation will dependl 'to a great extent upon the character lof 'the distillate desired and the character of the oil being treated., The separate liquid produ cts separated from the vapors in the columns 24, 43A and that collected in the final condenser 57 will consist of distillates of a relatively -dili'erent character. That is, there will be separated out of the lirst column a condensate of boiling point tha-n that'separated out in the subsequent stages. The boiling points and gravities of the different condensates will vary with the character of the fractionating conditions. pressures in the successive stages of fractionation and condensation will govern to a great extent the condensates and distillates obtained.

a relatively higher v That is, the temperatures and to maintain relatively higher pressures; f

that is, pressures ranging from 50 to 300 lbs. per square inchin theheating, vaporiz? ing and initial dephlegmating stages and reducing the pressure in the first fractionating column from 25 to 50 lbs., and a second reduction to 10 or 15 lbs. or to atmospheric conditions in the secondary fracti'onating column43. l

A further reduction may be effected by the valve 58 if any pressure is maintained on the secondary. column 43. y I This. process has the advantage that the pressure 'distillate vapors may he run directly through fractionating columns at re' duced pressures, whereby distillates or con densates .are obtained, which are` substantially 'the same in charater as would. be obtained bysubsecuent distillation;

'Ihe character of the apparatus may be varied without departing from the spirit of the invention.

' temperature -in a heating zone, collecting the heated oil in a substantial body in a vaporzing zone and causing the heating and vaporizationto take place under substantial pressure of the evolved vapors, passing the vapors to .a dephleguiating zone and there subjecting them to the refiuxing action of the incoming raw oil, passing the uncondensed vapors under reduced pressure con-V ditions to successive fractionating zones, condensing and Icollecting the uncondensed vapors passing over from the iinal zone, and returning selected portions of the condensate from each of the separate fractionating zones to the preceding fractionating zone.

2. A process for cracking hydrocabon oil consisting in raising the temperature in a heating zone, collecting the heatedoil in a substantial body in a vaporizing zone and causing the heating and vaporization to take place under substantial pressure of the evolved vapors','passing the vapors to a dephlegmating zone, and there subjecting them to the reluxing action of the incoming raw oil, passing the uncondensed v vapors under reduced pressure conditions to successive fractionating zones, condensing and collecting the uncondensed vapors passing over from the final zone, and collecting and returning selected portions of the con- 'sequent to .vapors under reduced through successive fractionatmg zones, condensate produced in each of the separate fractionating zones to the preceding zone, and directing portions to the heating zone -to be retreated.

3. A process for cracking hydrocarbon oil consisting in utilizing the chargin stock as a dephlegmatingmedium, lcharging the oil thence to a heating stage and transferring the oil in a heated condition to a vaporizing zone and there maintaining it in a substantialbody during vaporization, passing the evolved vapors to and throughadephlegmating zone and maintaining a substantial pressure uponwthe heating, vaporizing and dephlegmating zone, releasing the pressure subdephlegmation and passing the ressure conditions oil to a conversion.

densing and collecting the vapors from the.

final zone, collecting the condensate from each of the separate fractionating zones andv returning selected portions to the preceding zone and recycling portions to the heating zone for retreatment.

4 L A process for cracking hydrocarbon oil, consisting in raising the oil to a conversion temperature in a heating zone,'passing the heated oil to anenlarged lzone Where va-l porization occurs, lin cooling the evolved vapors by passing the same to-a primaryv -dephlegmating zone, in maintaining a super-v atmospheric pressure on-the oil undergoing conversion and on the vapors passing through the'deplil'egrnating zone, in'subjecting zone to the reiiuxing action' of chargin oil passing in heat conductive relation wit ing such vapors in the primary dephlegmatressure lower than the'pressure maintained l in the primary dephlegmating zone and Where further fractionation occurs, in returning portions of the condensate 'produced in said succeeding zone to the preceding primary dephlegmating zone, and in discharging from saidsucceeding fractionating zone uncondensed gasoline-like vapors for further condensation and collection.

5. A' process Jfor cracking hydrocarbon oil, consisting in raising the oil to a conversion temperature in a heating zone, passing the 4heated oil to an enlarged zone Where vaporization occurs, cooling the evolved va-l pors by passing the same to a primarydephlegmating zone, in maintaining a superatmospheric pressure on the oil undergoing conversion and on the vapors passing through the dephlegmating zone, in dis-I charging uncondensed vapors from the irimary dephlegmating zone to a succee ing zone maintained under a pressure lovverA than the pressure maintained in the primary dephlegmating zone and where further fractionation occurs, in returning portions of the condensate produced in said succeedingl collection.

CARBON' P. DU'BBS. 

